Refining of lubricant oils



United States Patent 3,112,259 REFINING 0F LUBRICANT OILS JacquesGrawitz, Le Havre, France, assignor to Societe Anonyme dite: CompagnieFrancaise de Raflinage,

Paris, France, a corporation of France N0 Drawing. Filed Apr. 14, 1960,Ser. No. 22,085

Claims priority, application France Apr. 14, 1959 Claims. (Cl. 208-264)It is known that the production of lubricating oils entailing extractionby means of solvents and the removal of paraffin necessitates a finaltreatment by means of absorbent substances, such as activated earths, inorder to improve the color of the commercial products and give them goodstability. This treatment by means of decolorizing earths has a numberof drawbacks, however; it necessitates very large installations; thedischarge of the used earths ultimately presents a difficult problem;and it involves a loss of advantageous products, the used earths beinghighly impregnated by the treated products when it is necessary todiscard them.

Other finishing processes have been proposed to obviate these drawbacks,and more especially catalytic refining processes in the presence ofhydrogen.

The present invention relates to an improved method of catalytictreatment for lubricating oils obtained from the distillates ofpetroleum products, in order to improve the odor, color and stability ofthe commercial products.

.This method comprises bringing the oily distillates, which havepreferably been previously refined by solventextraction and from whichthe parafiin has preferably been previously removed, into contact, inthe presence of hydrogen, with a particularly effective catalyst (whichwill be indicated hereinafter), and in operating under conditions suchthat there is practically no reduction of the sulfur compounds presentin the treatedv oil, because it has been found that these, acting asnatural inhibitors, have a favorable action as regards the stability ofthe finished products.

Furthermore, it is known that the usual hydro-desulfurizing catalystsare oxides or sulfides of cobalt and molybdenum, free or combined,deposited on porous supports.

The applicant, however, has observed that if these catalysts are usedfor a refining treatment aimed more especially at decolorizing andstabilization of lubricating oils and requiring very selectivehydrogenation conditions, which do not alfect the sulfur compounds, andat temperatures substantially lower than those required'for thedesulfurizing of lighter products than oils, the results can be greatlyimproved by an improvement of the technique, this improvement being thesubject of the present invention.

According to the invention, there is used for the hydrorefining of oilsin the presence of hydrogen a selective hydrogenation catalystcontaining oxides of metals of the VIth group and of the VIIIth group,which are deposited on oxides of metals of the IIIrd and IVth group orof the IInd group, which catalyst has been subjected, in the presence ofhydrogen, to the prior action of a petroleum distillate rich in sulfur,selected, for example, from the range of distillation of gas oils orlamp-oils.

The following examples illustrate this technique, and show thesuperiority of the latter over previous processes.

EXAMPLE I Two catalysts on the basis of molybdenum oxide and cobaltoxide, one of which is deposited on activated alumina and the other onmagnesia, were tested.

In a first operation, the furnaces charged with each of these catalystswere fed with an oily distillate of a viscosity of 33.7. centistokes at210 F. after refining with furfural and removal of parafiin; thetreatment was 3,1 12,259 Patented Nov. 26, 1963 carried out at 350 C.under 30 kg. per square centimeter pressure with a feed rate of 5v./v./h. (volume of charge per hour and for 1 volume of catalyst) and ahydrogen recycle of 355 cubic meters per cubic meter of charge. (Seebelow: tests I and III.)

In a second operation, the furnaces charged with the same catalysts werefed in the first instance with a gas oil containing 1.2% of total sulfurat the rate of 3 volumes per volume of catalyst and per hour, at 400 C.,under a pressure of 30 kg. per square centimeter with a hydrogen recycleof 500 cubic meters per cubic meter of gas oil; this treatment wascontinued for 12 hours. After this first treatment, the supply of gasoil is discontinued and the oily distillate identical to that of thepreceding test is injected at a rate of 5 v./v./h. after the temperaturehas been lowered to 350 C. and the hydro gen recycle brought to 355cubic meters per cubic meter of oily distillate (tests II and IV). Theresults of these twoseries of tests are given in Table I, which showsthe advantage of the pre-treatment in the qualities of the color andstability of the oils obtained in comparison with the treatment on thecorresponding catalyst which has not undergone this pre-treatrnent.

EXAMPLE II A catalyst obtained by making a paste of heavy magnesia withan ammoniacal solution of cobalt molybdate has the following compositionafter drying at 400 C.:

Percent MgO 88 M00 10 C00 2 An oily distillate refined with furfural andfrom which the parilfin has been removed, and the viscositycharaceristics of which at 210 F. are 12.3 centistokes, is treated onthis catalyst.

The treatment is carried out at 350 C. under 30 kg. per squarecentimeter pressure with a rate of feed of 8 v. v./ h. and a hydrogenrecycle of 355 cubic meters per cubic meter of charge.

After 48 hours operation on this catalyst, a sample of the productobtained is analyzed. The catalyst is then activated, the furnace beingfed with a batch of illuminating oil containing 0.170% of total sulfur,at the rate of 4 volumes per volume of catalyst per hour, thetemperature being increasedto 370 C., and the hydrogen recycle beingraised to 400 cubic meters per cubic meter of, gas .oil. Theilluminating oil treated now contains only 0.008% of sulfur. After 10hours operationunder these conditions .the oily distillate is againsupplied, the initial operating conditions being restored.

Comparison of the qualities of the products obtained will be clear fromTable II.

An oily distillate, refined by extraction with furfural and removal ofthe parafiin, of a viscosity of 8.62 centistokes at 210 F., is treatedon a catalyst containing oxides of molybdenum and cobalt deposited onmagnesia. The treatment is carried out at 310 C. under 30 kg. per squarecentimeter pressure at a rate of feed of 8.5 v./ v./ h. and a hydrogenrecycle of 235 cubic meters per cubic meter of charge.

After 48 hours operation on this catalyst a sample of the productobtained is analyzed, and activation of the catalyst is then effected,the reactor being fed with a gas oil containingfi 1.2% of sulfur at 400C. under 30 kg. per square centimeter pressure at a rate of feed of 5v./v./h.; the treatment conditions being such that the sulfur content ofthe gas oil is brought to 0.10%

After 15 hours of this activation treatment the supply of gas oil isdiscontinued, and paraffin distillate is again treated under the sameconditions as in the first stage.

After 48 hours of operation the product obtained is again analyzed.

The qualities of the products treated are apparent from Table III.

A catalyst comprising nickel tungstate deposited on an alumina andsilica support is used for the hydro-refining of an oily distillate asin Example II. The results are apparent from Table IV.

Table IV Product treated on- Fresh charge Initial catalyst, NiPre-treated tungstate Catalyst +A120a +Sin Duration, hours 50 50 D 150.8886 0.8870 0. 8868 12.34 12.38 12. 40 8 3% In the industrialapplication of the process, it has been found that the advantage of thepre-treatment according to the present invention is maintained duringthe entire life of the catalyst, the improved activity of which isretained for a practically unlimited time.

On the other hand, the catalyst which has not undergone anypre-treatment in no way improves with the period of use under theoperating conditions obtaining in the hydro-refining of oils.

What I claim is:

1. In a process for the finishing treatment of refined lubricating oilfractions to improve the odor and color and stability thereof bycatalytic action of hydrogen without affecting substantially the sulphurcontent of said fractions, the steps which comprise providing a catalystfor said catalytic hydrogen action including an oxide of a metalselected from groups VI and VIII of the periodic table, said metal oxidecatalyst being deposited on a supporting material therefor including anoxide of a metal selected from groups II and III and IV of the periodictable, activating and enhancing the effectiveness of said catalyst in apre-treating step by subjecting said catalyst on said supportingmaterial in the presence of hydrogen to the action of a petroleumdistillate different from said lubricating oil fractions and including asubstantial proportion of reactive and removable sulfur with consequentremoval of sulfur from said petroleum distillate, and thereaftersubjecting said lubricating oil fractions to the action of hydrogen inthe presence of said thus activated and enhanced catalyst effecting saidfinishing improvement in the odor and color and stability of saidfractions substantially in the absence of sulfur removal therefrom.

2. In a process for the finishing treatment of refined lubricating oilfractions to improve the odor and color and stability thereof bycatalytic action of hydrogen thereon without affecting substantially thesulfur content of said fractions, the steps which comprise providing acatalyst for said catalytic hydrogen action including an oxide of atleast one metal selected from groups VI and VIII of the periodic table,said metal oxide catalyst being deposited on a supporting materialtherefor including an oxide of at least one metal selected from groupsII and III and IV of the periodic table, activating and enhancing theeffectiveness of said catalyst in a pre-treating step by subjecting saidcatalyst on said supporting material in the presence of hydrogen to theaction of a petroleum distillate including a substantial proportion ofsulfur, and there after subjecting said lubricating oil fractions to theaction of hydrogen in the presence of said thus activated and enhancedcatalyst effecting said finishing said fractions substantially in theabsence of sulfur removal therefrom.

3. In a process for the finishing treatment of refined lubricating oilfractions to improve the odor and color and stability thereof bycatalytic action of hydrogen thereon without aflecting substantially thesulfur content of said fractions, the steps which comprise providing acatalyst for said catalytic hydrogen action including an oxide of ametal selected from groups VI and VIII of the periodic table, said metaloxide catalyst being deposited on a supporting material thereforincluding an oxide of a metal selected from groups 11 and III and IV ofthe periodic table, subjecting said catalyst on said supporting materialto a pre-treating step in the presence of hydrogen to the action of apetroleum distillate including a substantial proportion of sulfur, andthereafter subjecting said lubricating oil fractions to the action ofhydrogen in the presence of said thus pre-treated catalyst effectingsaid finishing said fractions.

4. A method as recited in claim 3 in which said petroleum distillateutilized in said pre-treating step for said catalyst is within thedistillation range of kerosene and gasoline and contains about 0.5% to2% total sulfur.

5. A process as recited in claim 3 in which said pretreating step forsaid catalyst is effected in a temperature range of about 360 C. to 420C., and with removal of about 70% to 95% of the sulfur in said petroleumdistillate.

6. A process as recited in claim 3 in which said finishing treatment ofsaid lubricating oil fractions is elfected at a temperature of about 250C. to 360 C.

7. A process as recited in claim 3 in which said catalyst comprisesmolybdenum and cobalt oxides and said supporting material comprisesalumina.

8. A process as recited in claim 3 in which said catalyst comprisesmolybdenum and cobalt oxides and said supporting material comprisesmagnesia.

9. A process as recited in claim 3 in which said catalyst comprisescobalt molybdate and said supporting material comprises alumina.

10. A process as recited in claim 3 in which said catalyst comprisescobalt molybdate and said supporting material comprises magnesia.

References Cited in the file of this patent UNITED STATES PATENTS2,706,167 Harper et a1 Apr. 12, 1955 2,878,180 Watkins Mar. 17, 19592,904,505 Cole Sept. 15, 1959 2,921,025 Holm et al Jan. 12, 19602,936,281 Annable et a1. May 10, 1960 2,967,144 Cole Jan. 3, 1961

1. IN A PROCESS FOR THE FINISHING TREATMENT OF REFINED LUBRICATING OILFRACTIONS TO IMPROVE THE ODOR AND COLOR AND STABILITY THEREOF BYCATALYTIC ACTION OF HYDROGEN WITHOUT AFFECTING SUBSTANTIALLY THE SULPHURCONTENT OF SAID FRACTIONS, THE STEPS WHICH COMPRISE PROVIDING A CATALYSTFOR SAID CATALYTIC HYDROGEN ACTION INCLUDING AN OXIDE OF A METALSELECTION FROM GROUPS VI AND VIII OF THE PERIODIC TABLE, SAID METALOXIDE CATALYST BEING DEPOSITED ON A SUPPORTING MATERIAL THEREFORINCLUDING AN OXIDE OF A METAL SELECTED FROM GROUPS II AND III AND IV OFTHE PERIODIC TABLE, ACTIVATING AND ENHANCING THE EFFECTIVENESS OF SAIDCATALYST IN A PRE-TREATING STEP BY SUBJECTING SAID CATALYST ON SAIDSUPPORTING MATERIAL IN THE PRESENCE OF HYDROGEN TO THE ACTION OF APETROLEUM DISTILLATE DIFFERENT FROM SAID LUBRICATING OIL FRACTIONS ANDINCLUDING A SUBSTANTIAL PROPORTION OF REACTIVE AND REMOVABLE SULFUR WITHCONSEQUENT REMOVAL OF SULFUR FROM SAID PETROLEUM DISTILLATE, ANDTHEREAFTER SUBJECTING SAID LUBRICATING OIL FRACTIONS TO THE ACTION OFHYDROGEN IN THE PRESENCE OF SAID THUS ACTIVATED AND ENHANCED CATALYSTEFFECTING SAID FINISHING IMPROVEMENT IN THE ODOR AND COLOR AND STABILITYOF SAID FRACTIONS SUBSTANTIALLY IN THE ABSENCE OF SULFUR REMOVALTHEREFROM.